docs: def min_geodetic_distance(a, b):
      """
      Compute the minimum distance between first mesh and each point
      of the second mesh when both are defined on the earth surface.
  
      :param a: a pair of (lons, lats) or an array of cartesian coordinates
      :param b: a pair of (lons, lats) or an array of cartesian coordinates
      """
      if isinstance(a, tuple):
          a = spherical_to_cartesian(a[0].flatten(), a[1].flatten())
      if isinstance(b, tuple):
          b = spherical_to_cartesian(b[0].flatten(), b[1].flatten())
      return cdist(a, b).min(axis=0)